1. Field of the Invention
This invention relates to a press key, and more particularly to a press key that is easy to assemble.
2. Description of the Related Art
Referring to FIGS. 1 and 2, a conventional press key 1 comprises a metal plate 11, a circuit board 12, an elastic restoring unit 13, and a keycap 14 adapted to be pressed.
The metal plate 11 is, for example, molded to have a patterned surface 111 with projections and recesses so as to engage the elastic restoring unit 13.
The circuit board 12 is disposed on the metal plate 11, and has a predetermined trace pattern that is designed to correspond to the patterned surface 111 of the metal plate 11.
The elastic restoring unit 13 includes a scissors-type lever 131 and an elastic member 132. The scissors-type lever 131 is connected to the keycap 14 and the patterned surface 111 of the metal plate 11, so that the keycap 14 can move upward and downward relative to the metal plate 11. The elastic member 132 is made of a rubber material that has a resilient restoring force and is disposed between the circuit board 12 and the keycap 14. When the keycap 14 is pressed by an external force, the elastic member 132 is deformed to contact the circuit board 12 to produce a signal. When the external force is removed from the keycap 14, the elastic member 132 may restore to move the keycap 14 away from the circuit board 12 by virtue of the resilient restoring force.
The disadvantage of the conventional press key 1 is that, in order to match the arrangement of the scissors-type lever 131, the patterned surface 111 with projections and recesses for fixing the scissors-type lever 131 must be formed using, for example, a mold. Therefore, the manufacturing cost is high. In addition, the circuit layout of the circuit board 12 is restricted by the arrangement of the elastic restoring unit 13.
Besides, to see clearly and use the press key in a dark place, a conventional light-transmissive press key 1′ has been developed based on the configuration of the press key 1 shown in FIGS. 1 and 2 (see FIG. 3). The light-transmissive press key 1′ has a keycap 14 that is made of a transparent material, and a light-guiding member 15 that includes laminated light-guiding sheet and reflective sheet. Due to the patterned surface 111, the light-guiding member 15 can only be mounted on a bottom surface of the metal plate 11, and most of the light guided by the light-guiding member 15 may be reflected or blocked by the metal plate 11. Therefore, the brightness of the light-transmissive press key 1′ is not sufficient and the illumination is not uniform.